The trick isn't to make it bigger, but to make it just as big but different enough.
So instead of Hulk v. Loki, its an all out battle between Thanos and all the Avengers at once. Just don't make the same scene again and again.

In all honesty, I think the GA got more of a thrill when Hulk one-punched the Leviathan. In my opinion, Hulk/Loki will not be hard to top at all. Personally I'd like to see Cap do something incredible and heroic, or Thor to just let loose.

What made the Hulk v. Loki scene memorable, and special, is the fact that it completely undermined the expectations of the audience. It was kind of like a slight of hand.

It's the same thing that happens in Raider's of the Lost Ark when Indy shoots the swordsman after the flashy display.

So you need another incident that will undermine the expectations of the audience without leaving them feeling cheated.

A quick idea off the top of my head:

- To show how powerful Thanos is, physically, have the Hulk bull-rush him and throw his fist directly into his chest. However, at the last moment Thanos catches the Hulk's fist without so much as wincing. There's an awkward moment where the Hulk just looks up at Thanos with a look on his face, not unlike a confused child, before Thanos tosses the Hulk aside.

Not my best idea, but it's early and I need more coffee. It would certainly get both the chuckle and it would serve to show the power of Thanos.

Which is why it will work. Audience gets emotionally attached/involved in the movie. Any avenger who tries to fight thanos 1v 1. including Hulk will get stomped. Which is why I think they should have Hulk and thor each fight thanos, only to get beaten, they are having words...hulk tackles thanos off screen and starts whaling on him. Givse a smart ass comment and leaves thanos on the ground, thanos gets up laughs and tells hulk he hasn't tested himself in hand to hand physical combat in centuries, and is ready to go at it again, and he tells the other avengers to stand down. Hulk gets angry, thor gets read, and hulk puts his hand up, and tells thor, "you heard him"...

they both start to fight, in a relatively..even fight..strength wise...thanos is landing way more blows due to his fighting abilitity, they taunt and brawl with hulk slowly evening it, before thanos starts to get pissed, and charges his punches with cosmic energy, then proceeding to pummell hulk bad, to the point where the audience gets concerned, thor tackles him off hulk, and thor and thanos go it it, full powers and fight, and thanos puts thor out of comition without too much effort, before he goes on to beat the rest of the avengers, before getting the IG and more plot induced stuff..

that's my ideal thanos vs avengers fight

starts as a calm thanos vs avengers, turns into hulk vs thanos, then thanos vs thor, then thanos vs the rest of the avengers before being defeated at the end. sounds like a fun battle

So, during an earlier battle (possibly pre-acquisition of the IG) Thanos is taking on the team in a fierce battle, but abruptly stops paying attention to them, and starts having a deep, involved discussion with Death... which of course, occurs on another plane of existence or in a construct of his mind, depending on how the audience wishes to interpret said conversation.

The Avengers continue their assault, but some kind of energy shield makes Thanos impervious to attack. The Avengers then temporarily cease their attack and basically just stand around looking awkward and confused. From their perspective, Thanos is just looking off to the distance and talking to himself.

Stark breaks the silence by deadpanning, "Well, they don't call him the Sane Titan..."

* Of course, for this to work, the audience must be aware that Thanos is referred to as the Mad Titan, which can easily be set up previously.

So, during an earlier battle (possibly pre-acquisition of the IG) Thanos is taking on the team in a fierce battle, but abruptly stops paying attention to them, and starts having a deep, involved discussion with Death... which of course, occurs on another plane of existence or in a construct of his mind, depending on how the audience wishes to interpret said conversation.

The Avengers continue their assault, but some kind of energy shield makes Thanos impervious to attack. The Avengers then temporarily cease their attack and basically just stand around looking awkward and confused. From their perspective, Thanos is just looking off to the distance and talking to himself.

Stark breaks the silence by deadpanning, "Well, they don't call him the Sane Titan..."

* Of course, for this to work, the audience must be aware that Thanos is referred to as the Mad Titan, which can easily be set up previously.

I would like to see a reversal of the Hulk - Leviathan beatdown in the first film. Hulk prepares to land a haymaker upon Thanos, but the Mad Titan uses his awesome mental powers to turn him back into Banner mid-swing. Banner smiles sheepishly at Thanos after his weak blow lands, and then is whisked away quickly by Thor before Thanos can land a return blow.